The present invention relates to a locking bolt for a towing device.
Numerous types of securing bolt devices are known for releasably securing structural components, including spring-loaded plugs or pins (as described in Standard DIN 11,024) and spring-loaded bolts.
U.S. published patent application A 2002/0069681 shows fasteners with locking pins which are installable and removable from a joint or other installation. A prior art locking pin has a cylindrical shank having a head member formed at one end. A transverse bore runs through the shank near the opposite end. The bore receives a cotter pin with a leg which may be bent to prevent removal of the bolt from the bore.
Netherlands published application No. NL A 285227 describes, inter alia, a securing device for machine elements, having a bolt which has a transverse bore near its end and has an axial blind hole at its end face. The securing device also includes a round steel wire blocking member. One end of the steel wire is received by the transverse bore and the other end is received by the blind hole. Between its two ends the steel wire forms a loop which extends laterally from the bolt. This securing device is difficult to loosen by hand, and is therefore unsuitable for use in situations such as towing elements, where the connection must frequently be released.